Background: The unsafe medication administration is one of the most medication related problems which causes harm and death to the patients and threatens the healthcare system. Given medication administration is predominantly the role of nurses. This study was aimed to explore the nurse’s experience of unsafe medication administration at public hospitals in Harari region, eastern Ethiopia. Methods: A phenomenological study design was conducted and the data were collected from 11 nurses from March 1 to March 31, 2019. The tape recorder and note taking was used to collect the data by in-depth interviews and key informant interviews. Open code software version 3.4 was used to write memos, coding and categorizing under their inductive thematic areas. Thematic analysis method were used.Result: The study had explored nurse’s experience and contributing factors for unsafe medication administration. Nurses have reported that they have ever experienced unsafe medication administration like, wrong time, medication, patient and self-stick injury during their practice. i) Organizational factors: inadequate resource, lack of clear policy and job description, lack of supervision and poor collaboration among staffs. The identified themes were, ii) Precondition challenges: expensive medication, frequently changed and too much prescription for a single patient, new medications with limited information. iii) Individual nurses factor: work absenteeism, lack of training and knowledge gap.Conclusion: The organizational culture, precondition challenges and individual nurse’s factors was found to be a major factors linked to unsafe medication administration practice. So tailored intervention is needed to reduce the unsafe medication administration in nursing practice.